Nomomechanical calculating apparatus



, mum ma HUUi P 2233-414 5R Nov. 5, 1940. FAGERHQLM 2,220,399

NOMOMECHANICAL CALCULATING APPARATUS Filed Jan. 9, 1939 2 Sheets-Sheet 1Invenian- 16 Erik Eqgerholm,

m5 REGISTERS Nov. 5, 1-940.

E."FAGERHOLM NOMOMECHANICAL CALCULATINQ APPARATUS Filed Jan. 9. 1939\llllllll 2 Shegts-Shset 2 235. fiEGISl Hi5.

Patented Nov. 5, 1940 UNITED STATES @SQTCH PATENT OFFICE NOMOMECHANICALCALCULATING APPARATUS Erik Fagerholm, Stockholm, Sweden, assignor toHenry Wild Surveying Instruments Supply 00., Ltd, Heerbrugg,Switzerland, a, corporation of Switzerland Application January 9, 1939,Serial No. 250,053 In Sweden January 13, 1938 '2 Claims.

The present invention relates to a nomomechanical apparatus forcalculating the distance of a target out of the bearings thereofmeasured at the end points of a given base line of a length which isshort in relation to said distance.

The principal object of the invention is to provide an apparatus of thetype described which enables a rapid and correct determination of thedistance.

Another object of the invention is to provide an apparatus of the typedescribed in which setting members of the apparatus are connected with arotatable spindle or spindles the rotation of which determines theadjustment of the setting members and in which said setting members areintegral with each other so as to form an adjustable cross of rigidlyinter-connected rigid arms, which co-operate with adjusting means to setthe cross for the values influencing on the distance sought.

These and further objects of the invention will be best understoodaccording as the following description proceeds reference being had tothe accompanying drawings which form part of this specification.

On the drawings:

Fig. 1 is a diagram of the problem of calculation to be solved by theapparatus according to the invention.

Figs. 2, 2a and 3 are nomograms for the solution of this problem.

Fig. 4 is a diagrammatic plan view of a nomomechanical apparatusaccording to the invention.

With reference to Fig. 1, A and B are the end points of the base lineand M the target. The length of the base line is b and its bearing 'Ub,said quantities being considered to be known in advance. The bearings ofthe target measured from the end points A and B of the base line aredesignated by '01 and v2. The range MB designated by sis obtained fromthe equation:

sin (v Sill (01-112) As the range s is great in relation to the lengthof the base line b we may write with suflicient correctness sin (v1v2)=sin 1"(121'u'2) where 'Ul-\1]2 is expressed in minutes, which gives usIn order to calculate this equation by means of nomograms we give it thefollowing form:

where m and n are mere multipliers to be chosen with regard to thefields of variation of the various variables.

In Figs. 2 and 2a. a nomogram is shown for the solution of the aboveEquation 1. I0 is the scale for the length b of the base line, l2 thatfor the range s, that for v1v'2 and I6 that for sin (UbUl). The value ofb is set ofi on scale In at point II, and the values of 'Dl-U2 and sin(vb-v1) calculated from the measured angles in and w are set ofi onscales l4 and H at points [5 and I1, respectively. A straight line l8drawn through point ll parallel to the straight line [9 connectingpoints l1 and I 5 crosses scale 12 in point 20 at which the range 3sought is read off. The portions of the scales shown by dotted linescorrespond to fields of variation which need not be taken intoconsideration.

The nomomechanical apparatus according to the invention for the solutionof the above problem is based on the diagrams illustrated in Figs. 2 and2a with the diiference that the one half of the nomogram shown in Fig.2a. is turned through a certain angle in relation to the other shown inFig. 2, it being diflicult by mechanical means on setting to secure trueparallelism and free movements of rulers representing the lines l8 and[9 resulting in unreliable results. When electing an angle between thetwo halves of the nomogram of 90 degrees the two parallel lines [8, l9will be replaced by a right angle arm cross I8 I9 as shown in Fig. 3.

With reference to Fig. 4 which shows diagrammatically a plan view of anembodiment of the nomomechanical apparatus according to the inventionbased on the diagram of Fig. 3, l 0 designates as before the scale forthe base line. The scale l2 for the range s in Fig. 3 is constituted bya rod 22 displaceably mounted in bearings 24 and provided with a scale26 readable conjointly with a relatively fixed index 28. A screwthreadedrod 30 mounted for rotation but not for displacement in bearings 32corresponds to the scale 14 for U1IJ2 in Fig. 3. One double arm 34 of arigid right angle arm cross I35 displaceably mounted in bearings 36corresponds to the scale I6 for sin ('UbU1) in Fig. 3. A rigid rightangle arm cross 45 corresponds to the straight lines I8 I9 in Fig. 3.The angle between rods 22 and 30 and the angle between rod 34 and theguiding rod 56 for an index of the scale l0 are each equal to the anglethrough which the halves of the nomogram in Figs. 2 and 2a are turned inrelation to each other, thus in the example chosen equal to 90 degrees.7

One arm 38 of the arm cross 45 is displaceably guided in a sleeve 46rotatably mounted on a pivot 48 on rod 22. The arm 40 of the cross 45lying in the extension of arm 38 is displaceably guided in a sleeve 50rotatably mounted on a pivot 52 fixed to a block 54 slidable along afixed guiding rod 56. The scale I is readable conjointly with an index58 fixed to rod 56. The sliding block 54 may be locked to rod 56 bymeans of a set screw 51. Of the two other arms of the cross 45 one arm42 is displaceably guided in a sleeve 60 rotatably mounted on a pivot 62on rod 34 and the other arm 44 similarly mounted in a sleeve 66rotatably mounted on a pivot 68 fixed to a sliding nut 1|] engaging thethreaded rod 30.

Secured to rod 30 is a bevel gear I2 engaging a bevel toothing on thecasing I4 of a difierential gear the sun gears I6 and I8 of which aresecured to spindles 80 and 82, respectively. Secured to spindle 80 atthe outer end thereof is a handle 86. Secured to the outer end ofspindle 82 is a bevel gear 88 engaging a bevel gear 90 having preferablythe same diameter as gear 88 and secured to a shaft 92 which at itsouter end carries a handle 98. The spindles 80, 82 are each connectedwith a counter 84 and 94, respectively, adapted to indicate the rotationof the spindles, for instance in angular measure.

Fixed to shaft 92 is a bevel gear I00 engaging a bevel gear I02 fixed toa spindle I04 carrying at its other end the one sun wheel I06 of adifferential gear. The other sun wheel I08 of this gear is fixed to aspindle I I0 carrying at its outer end a handle II4. Also spindle H0 isconnected with a counter I I2 to indicate its rotation. The casing ofthe differential gear is provided with a toothing I I6 engaging a gearII8 on a spindle I20 rotatably mounted in bearings I22. At its endportions spindle I20 is threaded to form tangent screws I24 eachengaging a toothed sector I30 and I32, respectively, rotatable on pivotsI26 and I28, respectively. Rotatably mounted on each of said toothedsectors is an abutment roller I34 and I36, respectively, and bearing onsaid rollers under the action of springs I40 is the other double arm I38of the arm cross I35 including the rod 34.

The operation of the apparatus is as follows:

On scale I0 index 58 is set to indicate the length I) of base line andsliding block 54 is locked in set position by set screw 51. Handles 96and 86 are rotated, until counters 94 and 84 register the values of theangles in and 02, respectively. By means of the diiferential gear I4,I6, I8 rod 30 will thereby be rotated through an angle proportional toU1U2 causing the nut I0 to be displaced through a corresponding distancebringing with it the arm cross 45. Handle H4 is rotated until counterII2 registers the value of the angle 'Ub90. The rotation of handle 96 toindicate the angle in is also transferred to spindle I04 by the bevelgearing I00, I02. As spindle H0 is rotated through the angle 'Ub--90,spindle I20 will be rotated through an angle proportional to vbv190. Bymeans of the tangent screws I 24 this rotation is transferred to thetoothed sectors I 30, I 32. The ratio of transmission between thespindles I04, I I0 and the toothed sectors is such that the angle ofrotation of the sectors is equal to the variation of the angle b-U1.Thereb the arm cross I 35 will be displaced through a distanceproportional to cos (vbv190), that is sin (vbv1), carrying with it thearm cross 45. The adjustment of the arm cross 45 by the displacement ofnut and rod. 34

brings the index 28 opposite the particular mark on the scale 26 whichindicates the range 8.

By suitably adapting the ratios of the gears, the graduations of thescales I0 and 26 and the distance of the rollers I34, I36 to therespective pivots I26 and I28 the multipliers m and 11. may be chosen soas to suit in the best manner the purpose for which the apparatus isintended.

The reading-01f of the scale 26 may, of course, in known manner befacilitated by means of nonius, microscope or the like. The adjustmentof the rod 22 may also be utilized for setting any other reading-ofidevice, or its value may be directly introduced into a calculatingapparatus, e. g. a central instrument for fire direction in coastartillery or anti-aircraft batteries.

In such cases where the greatest rapidity is required for thecalculation of the range sought, especially when a great number ofrevolutions of the spindles 80, 82 and H0 is required for theintroduction of the angles, the rotation of said spindles is preferablyeffected by means of electric motors, e. g. in such a manner that eachspindle 80, 82 or H0 is actuated by two electric motors adapted torotate the spindle in opposite directions via a differential gear.

Means may be provided to limit the movement of its movable parts,especially that of the settin members, so as to prevent a greatermovement of said parts than that consistent with the mechanicalperformance of the apparatus. The field of movement of, for instance,nut I0 is limited by the length of the threaded portion of rod 30, andif the rotation of said rod is continued after the nut having attainedone of its end positions, there is a risk of the apparatus beingdestroyed or, at least, set out of function. Similarly the rotation ofthe toothed sectors I30, I32 is limited to a given angle on both sidesof the starting position shown in Fig. 4.

In the manually operated apparatus shown in the drawings said safetymeans may consist, for instance, of a device actuated by the settingmember at the end positions thereof so as to lock the casing of theappurtenant differential gear. Thereby a continued rotation of thespindle which moves the member towards the end position referred to doesnot cause any further actuation of the member but only a rotation of thetwin spindle. In the drawings such a safety device for rod 30 in theupper end position of the nut I0 is shown diagrammatically in Fig. 4.The device comprises a longitudinally displaceable rod I42 guided insuitable bearings I44 and having its lower end I46 formed to engage arecess I48 in the casing I4 of the differential gear and at its otherend an abutment I50 adapted to be actuated by the nut 10 when said nutattains its upper end positions. A spring I52 holds the rod I42 indisengaged position with a stop I 54 thereon bearing on the upperbearing I44. When attaining its upper end positions nut I0 strikes theabutment I50 moving the rod I42 upwardly against the action of thespring I52 and causing the lower end I46 of the rod to engage the recessI48 in casing I4 which thereby is locked. Further rotation of thespindle e. g. 80 which moves the nut upwardly results only in a rotationof the twin spindle 82 which may be read 01f on counter 94.

When the apparatus is operated electrically such a safety means maycomprise an electric contact device adapted to be opened in the upperend position of the nut and inserted into the circuit 0f the electricmotor the rotation of which causes the nut to be moved towards this endposition.

Evidently, such a safety device may be provided also at the lower endposition of nut 10 as well as at the end positions of the toothedsections I30, I32.

Such safety devices are of importance in such cases when after thedistance to a certain target M has been determined it is desired todetermine the distance to another target M Fig. 1 for which the anglesv1 and U2 differ considerably from those for the target M. In such casethe spindles and 82 ought really to be rotated simultaneously and atapproximately the same speed unless nut 10 be moved beyond its allowedfield of movement. However, this is difiicult to perform in practice,irrespective of the spindles being manipulated by different persons orby one and the same person either manually or electrically. By providingsafety devices of the above or any other kind at the end positions ofnut 10 it is possible first by means of handle 96 or the electric motordriving spindle 82 to effect a rough adjustment of the nut 10 wherebyspindle 80 is automatically brought along when the nut attains one ofits end positions. Only after this rough adjustment the handle 86 or theelectric motor driving spindle 80 need to be used.

The invention is not restricted to the embodiment shown in the drawingswhich may be modified in several respects without departing from theprinciple of the invention.

What I claim is:

1. A nomomechanical apparatus for calculating the distance of a targetout of the bearings thereof measured at the end points of a base line ofa given length which is short in relation to said distance, comprisingan adjustable cross of rigidly inter-connected rigid arms, meansassociated with one arm of the cross to adjust the cross for the valueof the length of the base line, means associated with a second arm ofthe cross to adjust the cross for the value of the sine of thedifference of the bearing of the base line and the bearing of the targetat one end point thereof, means associated with a third arm of the crossto adjust the cross for the value of the difference of the bearings ofthe target at the end points of the base line, and means associated withthe cross to indicate the total setting of the cross by said adjustingmeans and thereby the distance sought.

2. A nomomechanical apparatus for calculating the distance of a targetout of the bearings thereof measured at the end points of a base line ofa given length which is short in relation to said distance, comprisingan adjustable cross of four rigidly inter-connected rigid arms formingright angles with each other, means associated with a first arm of thecross to adjust the cross for the value of the length of the base line,means associated with a second arm of the cross to adjust the cross forthe value of the sine of the difference of the bearing of the base lineand the bearing of the target at one of the end points thereof, meansassociated with a third arm of the cross to adjust the cross for thevalue of the difference of the bearings of the target at the end pointsof the base line, and means associated with the fourth arm of the crossto indicate the total setting of the cross by said adjusting means andthereby the distance sought.

ERIK FAGERI-IOIM.

